The present invention relates to the local diffusion of information, particularly information of local relevance, using mobile devices; in particular, the present invention concerns limiting undue diffusion of messages containing the information
Mobile devices with communications capability are becoming ubiquitous, the most common being the cell phone and other devices employing cellular radio technology. Many services are being implemented using such devices and many more may be expected as information regarding the location or position of the mobile device becomes readily available through the implementation of location discovery within the mobile radio infrastructure.
One type of service that is emerging is the distribution of local information which is relevant only to a particular narrow geographic location and need only be communicated to people within that location. Such information is usually distributed as a result of a request generated from a mobile device, the request either including the device""s location or authorizing the obtaining of the device""s location from a location server of the mobile radio infrastructure. The locally-relevant information can also be pushed over the mobile radio infrastructure to mobile devices within a given locality, though the costs of doing so are high. The type of information which it is most desirable to be able to push is information with a certain immediacy to it either because the information will go out of date quickly or because the target audience is transitory. One example is where a theatre still has seats available for a show shortly starting, and would like to offer the seats at half price. Another example is information about consumer goods (particularly new products or products under special promotion) which a shop wishes to advertise to consumers passing by.
In view of the cost and complexity of using mobile radio networks to push information, it would be useful to have a different way of distributing local information which has immediacy to it.
It may also be noted that although, as indicted above, location information will become increasingly available, this will only be to users of certain types of devices (cellular radio devices, GPS-equipped devices). Other devices will not have the appropriate capability to directly access location information and will therefore not be able to benefit from the full range of location-based services. Even if a device does have access to location discovery technology, the level of accuracy may deteriorate in the prevailing conditions (receivability of base stations and satellites, interference from buildings etc.) reducing the effectiveness of location based services. In both the foregoing cases it would be desirable for accurate location information to be locally distributed (but only over a short distance so as not to unacceptably affect its accuracy).
A number of technologies exist for the short range communication of information between mobile devices. These technologies include infra-red based technologies and low-power radio technologies (including, in particular, the recent xe2x80x9cBluetoothxe2x80x9d short range wireless standard). Depending on the technology implementation, differing types of message propagation will be enabled including asynchronous message broadcast, and multicast and point-to-point duplex connections established after coordination and negotiation between communicating devices.
Temporary networks using collections of mobile devices are of current interest. In particular, the Ad Hoc Networks Working Group of the IETF (Internet Engineering Task Force) is looking at the situation where two devices can temporarily communicate for a short time, via intermediate mobile devices; in this case, there is assumed to be some sort of temporary connectivity between the two devices across a short-lived mobile network. This work is primarily aimed at scenarios such as people in a conference environment sending mail to one another via intermediate devices, a situation which is dynamic, but which will tend to be temporarily static. Another example of an Ad Hoc network is the connection of ships or tanks in a military situation, where the topology of the network is evolving, but gradually over a period of time.
It is an object of the present invention to facilitate the local diffusion of information.
According to the present invention, there is provided a method of locally diffusing information for presentation to users of mobile devices, the method involving propagating the information from an originating point in messages passed from device to device by non-wired short-range communication means of the devices, the number of copies of a message in propagation initially tending to increase due to the propagation activities of the receiving devices and then dying away as the devices implement propagation limitation measures for the message, at least one device being operative to send messages multiple times with the interval between retransmissions of the message being dependent on how many times the same message has been received by the device either in total or during a recent period.
As used herein, the phrase xe2x80x9cnumber of copies of a message in propagationxe2x80x9d includes both message copies in transit and message copies residing in a device that are still considered active for onward propagation.
According to another aspect of the present invention, there is provided a mobile device for locally diffusing information to other devices for presentation to their users, the mobile device comprising:
a message store;
a short-range wireless transceiver for receiving messages and storing them to said store, and for transmitting messages retrieved from the store;
a message receive/transmit counter for recording how many times each message is received and transmitted; and
a message-propagation controller operative to cause messages held in said store to be transmitted multiple times with the interval between retransmissions of each message being dependent on how many times the same message has been received by the device, either in total or during a recent period, as indicated by said counter.